Marine Trematosaurid Temnospondyls from the Early Triassic of Western Australia.

The Temnospondyls were an ancient group of Tetrapods, which are the sister group to the modern Lisamphibians (Frogs, Salamanders, and Caecilians), although they were in many ways more Reptile-like, with many apparently able to live completely away from water for much of their lives, while others colonised marine environments. The first Temnospondyls appeared in the Carboniferous, rapidly expanding to become one of the most diverse and abundant groups of terrestrial Vertebrates. The Temnospondyls remained a major group throughout the Permian and Triassic, but were badly affected by the End Triassic extinction from which they never recovered. A few Temnospondyl lineages persisted through the Jurassic and into the Early Cretaceous, when they finally disappeared.

The Trematosaurids were a group of Temnospondyls which migrated into marine environments in the Early Triassic, evolving to occupy a large marine predator role which had become vacant during the End Permian Extinction, and spreading throughout much of the world's environments. Trematosaurids have been described from Madagascar, Greenland, Australia, Pakistan, Spitsbergen, European Russia, the Russian Far East, Germany, and Jordan. 

To date, only a single species of Marine Trematosaurid (several others are known from clearly non-marine environments) has been described from Australia, Erythrobatrachus noonkanbahensis, which described in 1972 by John Cosgriff and Neil Garbutt on the basis of a composite of fragmentary cranial remains from the Early Triassic Blina Shale of the central-southern Kimberley region of far northwestern Western Australia, collected during a series of expeditions to the area in the 1960s.

The Blina Shale records a transgressive delta setting (setting where the land is extending into the sea over a delta system), which would have faced onto the East Gondwana interior rift seaway. These deposits record a mixture of saline, brackish, and freshwater environments, and have produced non-Trematosaurid Temnospondyls such as the Rhytidosteid, Deltasaurus kimberleyensis, the Capitosauroid, Warrenisuchus aliciae, and the Brachyopids, Batrachosuchus henwoodi, and Banksiops townrowi. A variety of other fossils have also been found within the Blida Shale, including the ubiquitous Triassic Saurichthyid Actinopterygian, Saurichthys, a variety of Ceolacanths, the Ptychoceratodontid Lungfish, Ptychoceratodus philippsi, the Sagenodontid Lungfish, Aphelodus anapes, the Ceratodontid Lungfish, Asiatoceratodus tiguidensis, several possible Sharks, Conodonts, Insects, Spinicaudatans and Lingulid Brachiopods, possible Pseudomonotid Bivalves, indeterminate Ammonoids, some possible Mollusc egg cases, burrow traces, palynomorphs (fossil pollen and spores), Achritarchs, Horsetails, and possible Lycopods. 

Temnospondyls from the Blina Shale are typically found in a disarticulated state, either as individual bones or accumulations, and show signs of having been transported before their final deposition, including weathering and sorting by size. This is consistent with deposition in beds with preserved ripple marks and thin cross-lamination, which is suggestive of a shallow, tidal environment. 

In a paper published in the Journal of Vertebrate Palaeontology on 22 February 2026, Benjamin Kear of the Department of Palaeobiology at the Swedish Museum of Natural History, Nicolás Campione of the Palaeoscience Research Centre at the University of New England, Mikael Siversson of the Western Australian Museum, and the School of Molecular and Life Sciences at Curtin University, Mohamad Bazzi of the Department of Earth and Planetary Sciences at Stanford University, and Lachlan Hart of the School of Education and Earth and Sustainability Science Research Centre at the University of New South Wales, as well as the Australian Museum Research Institute, reassess that material assigned to Erythrobatrachus noonkanbahensis from the Blinda Shale deposits, and draw new conclusions about the presents of Trematosaurid Temnospondyls in the Early Triassic of Western Australia.

The original material assigned to Erythrobatrachus noonkanbahensis included the holotype, WAM 62.1.46, two topotype specimens, WAM 71.6.22 and WAM 62.1.50, and a high-definition plaster caste of the holotype, WAM 62.1.59 (in taxonomy, a holotype is the specimen from which a species is described, any other specimen considered to belong to the same species as the holotype therefore belongs to that described species, but if the holotype is found to belong to the same species as the previously described holotype of another species, then the newer species is considered invalid; a topotype is a specimen asigned to a species which comes from the same location as the holotype). All of these specimens were placed in the collection of the Western Australian Museum, but when Kear et al. came to look for them, only WAM 62.1.50 and WAM 62.1.59 could be found, WAM 62.1.46 and WAM 71.6.22 having apparently been loaned to John Cosgriff in 1984, at which time he was working at Wayne State University in Detroit, Michigan. 

A search of the palaeontological collection of Wayne State University could not locate these specimens, although WAM 62.1.46 was subsequently found in a search for potentially related specimens in the collection of the University of California Museum of Paleontology, where it had been identified as cf. Tertrema sp., and given the identifier UCMP 65858. The collection of the University of California Museum of Paleontology was also found to contain a second high-definition plaster caste of this specimen, listed as UCMP 65850. The University of California Museum of Paleontology has subsequenty returned WAM 62.1.46 to the Western Australian Museum. 

Also found within the collection of the University of California Museum of Paleontology was a box labelled WAM 62.1.50, however, this was found to be empty, having been 'withdrawn for study' by John Cosgriff in August 1968.

Source locality for the Erythrobatrachus noonkanbahensis holotype (WAM 62.1.46) and referred material (WAM 62.1.50). Map of the Noonkanbah Station area with the Great Northern Highway (1) extending southeast of Derby towards Fitzroy Crossing in northwestern Western Australia. Outcrop areas of the Lower Triassic Blina Shale are shown with the overlying Erskine Sandstone, and Middle Triassic Munkayarra Shale. Kear et al. (2026).

Specimen WAM 62.1.46, the holotype of Erythrobatrachus noonkanbahensis is a steinkern internal cast from the naso-frontal region of the skull and vomero-palatine section of the palate. This, along with the plaster casts WAM 62.1.59 and UCMP 65850, show Erythrobatrachus noonkanbahensis to have had an elongate skull with a basally constricted rostrum, dorsolaterally facing orbits that are positioned close to the lateral jaw margin, broad nasals that contact the lacrimals posterolaterally, and possibly the septo-maxilla near the external bony nasal opening, anteriorly narrow interpterygoid vacuities that are bordered by transversely broad palatines, ctopterygoids apparently lacking large palatal tusks, at least at the ectopterygoid-palatine suture, and a narrow cultriform process of the parasphenoid that divides the interpterygoid vacuities along the palatal midline, and extends to a point level with the anterior edges of the choanae.

High-definition plaster cast (WAM 62.1.59) and holotype specimen (WAM 62.1.46/UCMP 69858) of Erythrobatrachus noonkanbahensis from the Blina Shale. (A) Cast, and (B) original internal steinkern of the naso-frontal section of the cranium in dorsal aspect. (C) Interpretation of the cranial sutures (solid/dashed lines), openings (black fills), and broken/plaster surfaces (hatching). (D) Skull reconstruction in dorsal aspect. (E) Cast and (F) original internal steinkern of the vomero-palatine section of the cranium in ventral aspect. (G) interpretation of the cranial sutures and openings. (H) Skull reconstruction in ventral aspect. Skull outlines based on Tertrema acuta and Hyperokynodon keuperinus. Abbreviations: ch, choana; cp, cultriform process of the parasphenoid; ec, ectopterygoid; fr, frontal; ju, jugal; la, lacrimal; mx, maxilla; na, nasal; nc, nerve channel cast; or, orbit; pf, postfrontal; pl, palatine; pr, prefrontal; pv, pterygoid vacuity; sm, septomaxilla; ?tb, possible palatal tusk base; vo, vomer. Scale bars equal 50 mm. Kear et al. (2026).

Specimen WAM 62.1.50 is an external impression of the vomerine palate showing multiple dental rows and anterior margins of the choanae. This is recorded as a paratype of Erythrobatrachus noonkanbahensis on its Western Australia Museum label (a paratype is a specimen other than the holotype of a species which is used in the formal description of that species), but as 'cf. Aphaneramma' (refer to Aphaneramma) on the label of the empty box at the University of California Museum of Paleontology, a label which Kear et al. assume reflects Cosgriff's original thoughts on the classification of the specimen. Aphaneramma is a cosmopolitan Trematosaurid Temnospondyl also known from the Early Triassic of Pakistan, Madagascar, Russia, and Svarlbard. 

WAM 62.1.50 appears to be similar in proportions to the skull of Aphaneramma gavialimimus, a large (skull-lenght about 400 mm) species of Aphaneramma described from Madagascar in 2017. It also has fine longitudinal bone ridges, which have previously been observed in members of the genera Aphaneramma, Wantzosaurus, and Cosgriffius. The choanae of WAM 62.1.50 are longitudinally offset, such that the left opening would have been displaced anteriorly relative to the right, something which has also been recorded in other specimens of Aphaneramma. In their 1972 description of Erythrobatrachus noonkanbahensis, Cosgriff and Garbutt identify this as being the result of displacement of the right choanae, which they believe was 'compressed and pushed forward from its original position', but which Kear et al. consider may be a diagnostic feature of the genus. Notably, WAM 62.1.50 shows several rows of vomerine teeth (teeth on the roof of the mouth), which are absent in WAM 62.1.46, suggesting the two do not belong to the same species. Vonerine teeth are found in Aphaneramma, as well as some other genera of Trematosaurid Temnospondyls, although the size and arrangement of those of WAM 62.1.50 do not appear to exactly match any previously described taxa. For this reason, Kear et al. return WAM 62.1.50 to the designation cf. Aphaneramma. 

Referred material (WAM 62.1.50) of cf Aphaneramma sp. from the Blina Shale. (A) Palate impression in ventral aspect (coated with ammonium chloride sublimate). (B) Interpretation of the palatal sutures, dentition (solid/dashed lines), and openings (black fills). Skull outline based on Aphaneramma gavialimimus. (C) Skull reconstruction in ventral aspect. Skull outline based on Aphaneramma gavialimimus. Abbreviations: ch, choana; mx, maxilla; tr, tooth row; vo, vomer. Scale bar equals 30 mm in (A) and (B); and 50 mm in (C). Kear et al. (2026).

Cosgriff and Garbutt apparently viewed the additional specimens assigned to Erythrobatrachus noonkanbahensis, WAM 71.6.22 and WAM 62.1.50, as developmental stages of the species, noting that they were smaller than the holotype, WAM 62.1.46. As WAM 71.6.22 could not be located, this assessment could not be evaluated for this specimen, but Kear et al.'s study clearly shows that the smaller size of WAM 62.1.50 only relates to its fragmentary nature, and that it was clearly derived from quite a large animal. Furthermore, it differs significantly in morphology to WAM 62.1.46, and cannot be assigned to the same species.

This expands the diversity of Temnospondyls known from the Blina Shale, and expands our knowledge of how that assemblage relates to wider Temnospondyl faunal distributions in the Early Triassic. This includes widespread Australian species such as Deltasaurus kimberleyensis, Warrenisuchus aliciae, and Banksiops townrowi, taxa also known from South Africa, such as the genus Batrachosuchus, species not found anywhere else, such as Erythrobatrachus noonkanbahensis, and now an example of the globally distributed genus Aphaneramma. This also increases the distribution of these marine Temnospondyls, raising the possibility that their distribution was not just due to expansion along the continuous coastal Tethyan periphery of the Pangean supercontinent, but may also have involved longer distance, ocean-crossing dispersals between Laurasia and Gondwana across the Tethys Ocean.

Early Triassic (about 250 million years ago) paleobiogeographic distributions of Erythrobatrachus noonkanbahensis (star) and Aphaneramma in Australia (star), Madagascar (circle), Pakistan (square), Svalbard (polygon); and Russia (triangle). Kear et al. (2026).

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Did the earliest Vertebrates have four eyes?

Vertebrates have complex, camera-type eyes which have been a source of interest to evolutionary biologists since the nineteenth century, when this seemed an unusually complex system, which it was difficult to imagine arising through a series of gradual steps. Modern evolutionary biologists are less concerned by this, recognising that even a very simple eye is better than no-eye-at-all, and that therefore a complex eye could arise step-wise from the simplest cluster of light-sensitive cells, but beyond this have been able to give no real explanation of what the eyes of our earliest Chordate ancestors looked like. 

Camera eyes comprise a comprise of a spherical lens, a retina, an iris, and a set of muscles exterior to the main eye structure, which can be used to alter the shape of the lens, enabling it to focus an image on the hemispherical retina, which are detected by the optic nerve, and transmitted to the brain.

Almost all modern Vertebrates have two lateral camera eyes, although some groups have lost these, and, curiously, some Lizards have a third such eye on the top or back of their heads, which is derived from the pineal complex of the brain.

Eyes in Vertebrate fossils are often identified by the preservation of the pigmentation from the retinal epithelium, which is rich in melanin, as dark stains, and/or by impressions left by the hard lens. The oldest purportative fossil Vertebrate eyes are seen in Metasprigginna walcotti, a probable Chordate from the Burgess Shale of Canada, dated to about 505 million years before the present. In these fossils a hemispherical shape has been interpreted as the retina, and an associated circular area as the lens. The earliest known example of melanostomes (the cells which contain the pigment melanin) being preserved in the eye of a Vertebrate is the Devonian Jawless Fish Euphanerops longaevus, from the Escuminac Formation of Canada, which has lateral eyes with abundant such cells, inferring the presence of a retina.

No non-Vertebrate Chordates possess a camera eye. The Lancets, or Amphioxi, have four clusters of photoreceptor cells, but are not thought to be able to produce an image (unsurprising since they also lack a brain). Salps, which are planktonic Tunicates, have a multiple stage life cycle, with an colonial adult phase which reproduces sexually, and a solitary adult phase which reproduces asexually. The larval form of the colonial Salp has three pigment cup eyes, while the larval form of the solitary stage has a single eye. During the embryonic development of Vertebrates, the paired eyes arise from a section of the anterior neural plate which also gives rise to the pineal organ, leading some biologists to speculate that these three organs are analogous to the three eyes of the Salp larvae. 

In a paper published in the journal Nature on 21 January 2026, Xiangtong Lei of the Center for Vertebrate Evolutionary Biology and Institute of Palaeontology at Yunnan University, Sihang Zhang, also of the Center for Vertebrate Evolutionary Biology, and of the State Key Laboratory for Vegetation Structure, Functions and Construction at Yunnan University, Peiyun Cong, also of the Center for Vertebrate Evolutionary Biology, and State Key Laboratory for Vegetation Structure, Functions and Construction at Yunnan University, as well as the Oxford University Museum of Natural History, Jakob Vinther of the Palaeobiology Research Group and School of Biological Sciences at the University of Bristol, Sarah Gabbott of the Centre for Palaeobiology & Biosphere Evolution at the University of Leicester, Fan Wei again of the Center for Vertebrate Evolutionary Biology, and State Key Laboratory for Vegetation Structure, Functions and Construction at Yunnan University, and Xing Xu, once again of the Center for Vertebrate Evolutionary Biology and Institute of Palaeontology at Yunnan University, and of the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, identify organs which they believe are eyes in two species of Myllokunmingids (Early Chordate Animals which may be ancestral Vertebrates) from the approximately 518-million-year-old Chengjiang Biota of Yunnan Province.

Lei et al. consider Myllokunmingids such as Haikouichthys ercaicunensis and Myllokunmingia fengjiaoa to be the earliest known Vertebrates. For their study they examined six specimens of Haikouichthys ercaicunensis and four slabs which each contained multiple specimens of an as yet unnamed new Myllokunmingid. In both species they found that the head region typically has four black spots, two larger spots being placed laterally on the head, and two smaller spots facing forward. Previous studies have identified the larger of these spots as eyes, while the forward-pointing spots have been identified as nasal sacs. 

General morphology of the lateral eyes and pineal complex with their preserved melanosomes in two species of Myllokunmingidae from the Chengjiang biota. (a)-(b) Haikouichthys ercaicunensis (YNGIP-90281) with its enlarged eye region (b). (c) Carbon (red) and iron (green) element mapping of the same region in (b), arrows denote the position of figured melanosomes in (g) and (h). (d) General morphology of the unnamed Myllokunmingid  (YNGIP 90291-b,). (e) Enlarged eye region of the unnamed Myllokunmingid (YNGIP 90292-a), illustrating lateral eyes (circles in dotted line) and pineal/parapineal organs (arrows). (f) Carbon (red) and iron (green) element mapping of the same region in (e), arrows denote the position of figured melanosomes in (i), (j). (g)-(h) Melanosomes in the eyes (g) and pineal complex (h) of Haikouichthys ercaicunensis. (i)-(j) Melanosomes in the eyes (i) and pineal complex (j) of the unnamed Myllokunmingid. Scale bars are 2 mm (a); 1 mm (d); 200 μm (b), (c), (e), and (f); 500 mm (g)-(j). Lei et al. (2026).

Energy dispersive X-ray, Raman spectroscopy, and X-ray photoelectron spectroscopic analysis of the lateral eyes and the forward facing spots are enriched in organic carbon. Examination under a scanning electron microscope revealed that these organic patches are made up of oblong or cylindrical microbodies, which measure 200-1200 nm in length, and 200-900 nm in width. Most of these microbodies appear deformed or fused together, and they are associated with pyrite minerals and a clay matrix.

In the lateral eyes of Haikouichthys ercaicunensis these microbodies are consistently oval in shape, ranging from 250 to 900 nm in length and from 200 to 800 nm in width. Element mapping suggests that these objects are carbonaceous structures with a small central hole. In the unnamed Myllokunmingid, there are two morphotypes of microstructures present, the first similar to those seen in Haikouichthys ercaicunensis, and the second being cylindrical in shape and between 400 and 1200 nm in length and between 200 nm and 550 nm in width. These structures also have a central hole. Transverse sections of the melanosomes of some living Vertebrates have also shown such a central hole.

Lei et al. next investigated the molecular composition of the microstructures using Time-of-Flight Secondary Ion Mass Spectrometry. This revealed that in both species the microstructures contained the pigments eumelanin and phaeomelanin, both of which are found in living Vertebrates, confirming that these structures are in fact melanosomes. 

The melanosomes in the lateral eyes of Haikouichthys ercaicunensis appear to be largely distributed on the horizontal axis, while those of the unnamed Myllokunmingid are spread along a diagonal axis, with the two types of melanosomes present having different distributions and pigment contents; the cylindrical cells have a higher eumelanin content (which would have made them browner in colour) while the ovoid cells have a higher phaeomelanin content (which would have made them oranger in colour). 

In living Vertebrates, melanosomes are found in the iris, choroid and retinal pigment epithelium, but layers of ovoid and cylindrical melanosomes are found only in the retinal pigment epithelium. The observed structures in the eyes of the unnamed Myllokunmingid are consistent with a retinal pigment epithelium with a similar structure. However, in the six specimens of Haikouichthys ercaicunensis examined only ovoid melanosomes could be observed. However, rather than interpreting this as a more primitive state, Lei et al. note that in the Lamprey Mayomyzon pieckoensis and the Cartilaginous Fish Bandringa rayi from the Carboniferous Mazon Creek Fauna of Illinois, a preponderance of ovoid melanosomes have also been observed in eye structures, and that relatively few living Vertebrates have have been investigated to determine what forms of melanosomes are present in their retinas.

In both Chengjiang Myllokunmingids, the central spots are smaller than the lateral spots, about 160-240 µm in diameter in Haikouichthys, and about 90-120 µm in diameter in the unnamed Myllokunmingid. These were also found to be carbonaceous in composition, and to contain microbodies which appeared to be melanosomes; in each species these were consistent with the bodies found in the larger lateral eyes, with only oval melanosomes in Haikouichthys and both cylindrical and oval forms in the unnamed Myllokunmingid. Based upon this, Lei et al. conclude that these medial organs are also preserved retinas.

Carbonaceous preservation of Myllokunmingids eyes and median dark s pots (a-h). (a)-(b) Haikouichthys ercaicunensis (YNGIP-90285) showing lateral eyes (grey) and pineal eyes (green) with lens (blue). (c) Carbon element map of Haikouichthys ercaicunensis (YNGIP-90285) head. (d)-(e) Haikouichthys ercaicunensis (YNGIP-90296) showing lateral eyes (grey) and pineal eyes (green) with lens (blue). (f) Carbon element map of Haikouichthys ercaicunensis  (YNGIP-90296), arrows indicating left pineal eye. (g)-(i) Eyes of Haikouichthys ercaicunensis showing lens (arrows). (g) YNGIP-90283. (h) YNGIP-90284. (i)  YNGIP-90289. (j), (m) lens in Elonichthys peltigerus (ROM56794). (k), (n) Lens in Platysomus circularis (PF7333). (l), (o) Lens in Bandringa rayi (ROM56789). Scale bars are 200 μm (a)-(f); 50 μm (g)-(i); and 500 mm (m)-(o). Lei et al. (2026).

As well as melanosomes within their retinas, both species show preserved lenses, which are ovoid in structure, and about one fifth of the size of the associated retinas. These structures are preserved as impressions with some relief, suggesting that they represent an original structure which was somewhat decay resistant. This placement, size, and composition is consistent with the interpretation of these structures as eye lenses, which are harder tissue than other components of the eyes, and have been found in other Vertebrate fossils, including the Middle Cambrian vertebrate Metaspriginna walcotti.

The similarity of the lateral eyes of the two Myllokunmingid species from the Chengjiang Fauna to those found in later Vertebrate fossils is taken by Lei et al. to indicate that camera eyes had appeared by the Early Cambrian. The combination of a large retinal pigment epithelium and smaller lens is consistent with a fluid-filled retinal sphere with an iris opening within which the lens is suspended, as seen in living Vertebrates. Such eyes would almost certainly have been capable of image formation, although the quality of such images is impossible to know. 

The median, forward-facing spots on Myllokunmingids have previously been interpreted as nasal sacs, or possibly pineal organs. The former explanation seems unlikely, as nasal sacs otherwise appear to have been quite a late development, not found in many later stem Vertebrates, and probably first evolving in Galeaspids (probable stem Gnathostomes) between 435 and 370 million years ago. Lei et al. report the discovery of melanosome-bearing tissues and lenses in these spots, which are again inconsistent with an interpretation as nasal sacs. They instead interpret them as paired pineal organs functioning as a second pair of camera eyes.

Lei et al. also note that the Middle Cambrian stem Vertebrate Metaspriginna walcotti also has a pair of dark spots between the lateral eyes, preserved as carbonaceous films, and that these also appear to have associated spherical objects, which may also have been lenses, suggesting that this species may also have had a second pair of median eyes.

In Lampreys, the pineal organ is photosensitive, helping the Animal to respond to changes in light levels within the environment. In Mammals, the pineal organ is entirely internal, but it is associated with aligning the neuroendocrine system with the day/night cycle. In Lizards, the pineal organ is also associated with the neuroendocrine system, but in some species retains a photoreceptive capacity. It has therefore previously been suggested that the pineal organ may have developed from some sort of precursor eye, something that has entered popular culture as the 'third-eye' theory. Lei et al. suggest that the pineal organ may have begun as a pair of photosensitive organs acting as additional camera eyes. 

The presence of complex visual systems in the earliest Vertebrates suggests that this sense was of key importance to the success of the group from very early in its history. Both the photoreceptive cells of Vertebrates and the cells of the retinal ganglion arise from nurosensory cell precursors also present in Tunicates. A theoretical model has previously been developed in which the camera eye developed via two rounds of whole-genome duplication, the first allowing for a divergence between the photoreceptor cells and the optical ganglion cells, the second between the pineal complex and the lateral eyes. The apparent presence of a second pair of camera eyes associated with the pineal complex in Early Cambrian Myllokunmingids may represent a transitional stage, in which the genes associated with the development of the eyes have been duplicated, but only just started to evolve towards the modern pineal complex.

Evolutionary scheme of visual system in early Vertebrates. (a) Thalia (Tunicata). (b) Haikouichthys. (c) Euphanerops. (d) Generalised Lamprey. (e) Sacabambaspis. (f) Shuyu. (g) Aphyocharax. Coloured regions show positions of key sensory organs: blue, eyes; red, pineal. Light grey lines represent body outlines. Coloured bars represent the suggested acquisition of key characters. Abbreviations: br, brain; p, pineal; pp, parapineal; TG, total group. Cyclostome represents the Petromyzontidae and Myxinoidea total groups and Gilpichthys, which was recovered in a polytomy with those two groups. Cyclostome and Gnathostome total groups in this topology recovered in a polytomy with Metaspriggina and (Haikouichthys + Myllokunmingia). Lei et al. (2026).

Euphanerops longaevus, an anaspid-like fossil from the Devonian Escuminac Formation of Canada, which has been suggested as a stem-Agnathan (jawless Fish) also has paired median dark patches which have been shown to be carbonaceous films with structures identical to the melanosomes of its lateral eyes. Living Lampreys have a pineal eye and a smaller parapineal eye, both of which have functioning retinas (but not lenses) and are used to detect changes in light conditions. The stem Gnathostome (jawed Fish) Sacabambaspis has two pineal openings, which Lei et al. suggest are analageous to the pineal and parapineal eyes of Lampreys. Later stem Gnathostomes, such as the Galeaspids, only have a single such opening, suggesting a progressive loss of this system. Crown Gnathostomes have lost this opening completely, but some have a preserved pineal window, with an area of thin, semitransparent skull overlaying a pigmented area associated with the pineal complex. Thus an image-forming pineal complex was slowly replaced with a light sensitive organ regulating the production of the hormone melatonin, which regulates sleep patterns. Most crown Vertebrates possess both pineal and parapineal organs, sugesing that this complex was originally paired.

During the Cambrian Explosion, early Animals went through a phase of remarkable morphological innovation, with each new development changing the ecological environment in which all Animals lived, particularly as predation became more common. It has been suggested that higher levels of ultraviolet radiation in shallow waters during the Cambrian may have made the rapid evolution of vision more important, although it is likely that the evolution of predator-prey relationships would have been sufficient to drive this. The appearance of large (for the Cambrian) predators such as Radiodonts, gilled Lobopods, and stem Chaetognaths, all of which developed complex visual systems, would have made it important for smaller, non-predatory Animals such as Myllokunmingids to develop equivalent systems to evade predation and survive. 

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Parafaveoloolithus xixiaensis: A new oospecies of Dinosaur eggs from the Upper Cretaceous of HenanProvince, China.

The Xixia Basin lies in Henan Province, China, to the east of the Qinling Mountains of southern Shaanxi Province, and extends roughly 100 km east-to-west, covering an area of about 518 km². Within this basin a series of Upper Cretaceous fluvial deposits overlie a Devonian basement. These deposits have been divided into three formations, the middle one of which, known as the Zhaoying (or sometimes Majiacun) Formation, comprises a 2120 m thick sequence beginning with motley argillaceous siltstones, sandstones and mudstones at the base, and grading into an upper layer comprising reddish mudstones and sandstones. This sequence, considered to have been laid down in a fluvio-lacustrine basin in an area with a generally arid climate, is noted for its production of preserved Dinosaur eggs, with at least seven described oospecies (because eggs are a record of a part of the life-cycle of an animal, can seldom be related to a species defined from body fossils, they are described under a parataxonomic system as oospecies, which are then organised into oogenera and oofamilies) from the Zhaoying and underlying Zoumagang (or Gaogou) formation, as well as ichnofossils (trace fossils), Dinosaur bones, Turtle eggs, and fossil Bivalves, Gastropods, Ostracods, Spinicaudatans, and Plants.

In a paper published in the journal Acta Palaeontologica Polonica on 17 December 2025, Qing He and Shutong Li of the School of Resources and Environmental Engineering at Anhui University, Shukang Zhang of the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, Yifan Huang of the Prevention and Control Center for Geological Disasters at the Henan Geological Bureau, Xiqiang Cao of the Henan Scientific Academy of Land and Resources, and Hongqing Li and Mengyuan Zhu, also of the School of Resources and Environmental Engineering at Anhui University, describe a new oospecies of Dinosaur eggs from the Zhaoying Formation of Xixia County.

The new species is placed in the oogenus Parafaveoloolithus, and given the specific name 'xixiaensis' meaning 'from Xixia'. The species is described from a clutch of 13 subspherical eggs arranged in a radial pattern. The individual eggs are 123.3–142.6 mm by 97.2–127.2 mm, with shells 123.3–142.6 mm and 97.2–127.2 mm thick. The shells have a single structural layer with no visible growth lines and a honeycomb structure with straight pore canals. 

A clutch of Dinosaur egg oospecies Parafaveoloolithus xixiaensis. YJYM-01–13 (each egg has unique repository number), from the Upper Cretaceous of the Xixia Basin, Henan Province, China. He et al. (2025).

The oogenus Parafaveoloolithus belongs to the oofamily Faveoloolithidae, which includes six genera from the Late Cretaceous of China, Mongolia, and South Korea. No fossil eggs from outside East Asia have been assigned to the oofamily (some 'Titanosaur eggs' from the Late Cretaceous of Argentina have been suggested as possible members of the family, but this is doubtful), suggesting that the egg-layers had a limited geographical distribution, although they are found in a variety of different palaeoenvironments.

Thin sections (SREE X13-01) of Dinosaur eggshell Parafaveoloolithus xixiaensis, (YJYM-13) from the Upper Cretaceous of the Xixia Basin, Henan Province, China. (A₁) A single structural layer composed of loosely arranged eggshell units and the straight pore canals between eggshell units; arrows indicate the secondary eggshell units. (A₂) A line drawing showing the eggshell units in radial section. (A₃) Enlargement of the gathered egg￾shell units; arrow points to the single eggshell unit. (A₄) Growth centres of the gathered eggshell units; arrows point to the six growth centres. He et al. (2025).

Very few eggs belonging to the Faveoloolithidae have been found in clutches to date, and Parafaveoloolithus xixiaensis is probably the best known example to date. The radial pattern in which the eggs are arranged suggests that this is a true representation of how they were deposited, rather than a result of transportation and redeposition. He et al. suggest that the pattern and porosity of the eggs implies the female Dinosaur would have deposited the eggs in a roughly circular arrangement, before covering them over with sand - something which would also have aided there preservation. 

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A new reconstruction of the Yunxian 2 skull, and its implications for the relationship between the 'Archaic Homo sapiens' of China and Modern Humans.

The Middle Pleistocene, or Chibanian (roughly 774 100 to 129 000 years ago), has produced a range of Hominin fossils, with a surprising range of morphological diversity. Recent finds from Callao Cave on Luzon Island in 2007 and Rising Star Chamber in South Africa in 2013, have led to the description of two new Human species, Homo luzonensis and Homo naledi respectively, from this age. 

China has produced a diverse assemblage of Chibanian and older Hominin fossils, often labelled as 'Archaic Homo sapiens', although their relationship to Modern Humans has been the subject of debate for a long time. The Yunxian 1 & 2 crania were discovered on on a terrace of the Hanjiang River in the Yunyang District (formerly Yunxian) of Shiyan City, in Hubei Province, China, in 1989 and 1990. These skulls have been dated to between 1.1 million and 940 000 years ago, and are considered important for the understanding of the genus Homo in China, and to a certain extent the world, although both are heavily distorted, hampering attempts to reconstruct their original morphology and therefore phylogenetic relationships. 

The Yunxian 2 skull. Although the least distorted of the two crania from Yunxian, it is still partially crushed, and therefore difficult to interpret. Garry Todd/Hubei Provincial Museum/Wikimedia Commons.

In a paper published in the journal Science on 25 September 2025, a team of scientists led by Xiaobo Feng of the School of History and Culture at Shanxi University, Hubei Polytechnic University, and the Institute of Yunxian Man Site and School of History, Culture and Tourism, at Hanjiang Normal University, Qiyu Yin of the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, and the College of Earth and Planetary Sciences of the University of the Chinese Academy of Sciences, Feng Gao of the Yunnan Institute of Cultural Relics and Archaeology, and Dan Lu, also of the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, and the College of Earth and Planetary Sciences of the University of the Chinese Academy of Sciences, present a new reconstruction of the Yunxian 2 skull, and discuss the implications of that reconstruction for the relationship between the 'Archaic Homo sapiens' of China and Modern Humans.

Our understanding of the relationship between Modern Humans and our extinct Hominin relatives is based almost entirely on the reconstruction of the anatomy of extinct species from fossil specimens, many of which are quite distorted. Of the three fossil crania discovered at Yunxian, one (Yunxian 3) is still under preparation, having been found in 2022. Both of the previously discovered specimens are distorted, with Yunxian 1 being quite badly crushed as well. Computed tomography scans of Yunxian 2 have suggested that most of the deformation is due to the fragmentation and displacement of parts of the skull, rather than actual warping of the material. Feng et al. built a digital reconstruction of this fossil, using software to move parts back into their original position, and filling in some gaps with data from Yunxian 1. 

The reconstructed cranium is large and long, with a braincase which appears flattened in lateral view. It is smaller than the Harbin Xuchang crania, approximately the same size as the as Kabwe, Petralona, Bodo, Jinniushan, and Sangiran 17 crania, and larger than the Jebel Irhoud 1, Dali, and Maba crania. The reconstruction still lacks small parts of the zygomatic arches and the central incisors, but is otherwise intact. It contains a number of traits associated with earlier members of the genus Homo, including a thick supraorbital torus, a broad basicranium and palate, a long and low vault in lateral view, a receding frontal con￾tour, and a rather flat parietal contour, and a high, anteriorly projecting face. However, it lacks other traits associated with early members of the genus, such as a strongly angulated occipital with a prominent transverse torus. The specimen lacks the occipital bun, forward projecting midface, and general rounded 'en bombe' shape of Neanderthal skulls, and the upper parietal expansion of Modern Humans. The zygomaxillary region is transversely flat and faces anteriorly, similar to the Harbin, Dali, Jinniushan, and Hualongdong crania from Asia, as well as specimens assigned to Homo antecessor from Europe, as wellas Modern Humans. Its cheek￾bones are large and high.

Reconstruction of the Yunxian 2 cranium in standard views. (A) to (F) Anterior, posterior, inferior, superior, left, and right views, respectively. Brown colour indicates the fossil bone. The zygomatic bone and the tip of the left maxilla, as indicated with dark brown, were grafted and reconstructed by incorporating elements of Yunxian 1. White colour indicates the reconstructed parts inferred from the fracture edge and Yunxian 1. Neutral grey indicates the bones crushed and covered by other bones and matrix. Scale bar is 5 cm. Feng et al. (2025).

The matrix filling the skull is dense, and does not produce a good contrast with the bone material in computed tomography scans, preventing analysis of the features of the interior of the skull. However, Feng et al. were able to calculate an endocranial capacity of 1143 cm². However, the frontal lobe appears low and narrow, little expanded from the situation in early Homo, and unlike the expanded frontal lobes of Neanderthals and Modern Humans. 

Reconstruction of the endocranial cast of Yunxian 2. (A to F) Anterior, posterior, inferior, superior, left, and right views, respectively. Scale bar is 5 cm. Feng et al. (2025).

The traits which can be measured suggest that morphologically, Yunxian 2 appears to be intermediate between early Homo species and specimens such as Home erectus, Homo ergaster, and the Kabwe and Petralona crania, and later Asian skulls such as Harbin, Dali, and Jinniushan. 

A phylogenetic analysis based upon the new reconstruction of Yunxian 2, found it grouped with a group of Asian specimens including Dali, Jinniushan, Xujiayao, and Hualongdong and the Xiahe and Penghu mandibles, which have together been referred to as the Homo longi clade, based upon the suggestion that the Xujiayao, Xuchang, Xiahe, and Penghu specimens, as well as the Denisovans should be grouped together as a new species, Homo longi (although Feng et al. did not recover the Xuchang specimens as part of this group). Feng et al.'s reconstruction found this clade to be the sister to Homo antecessor, with the Homo longi clade plus Homo antecessor being the sister clade to Homo sapiens. Yunxian 2 is the oldest member of the Homo longi clade as recovered by Feng et al., but not the earliest branching. 

Phylogeny and divergence time of 57 selected fossil operational taxonomic units from the genus Homo. The topology of the tree was the majority consensus of the most parsimonious trees from the parsimony analysis in TNT. The divergence time was inferred from the Bayesian tip-dating analysis in MrBayes 3.2. Branch lengths are proportional to the division age in thousands of years (Ka). Numbers at the internal nodes are the median ages, and the blue bars indicate the 95% highest posterior density interval of the node ages. The red half-brackets on the right indicate the ranges of the Neanderthal, Homo longi, and Homo sapiens clades. The numbers in red highlight the ages of division of the three clades. Yunxian is also highlighted in red. Feng et al (2025).

The term 'Denisovan' was coined for a group of highly fragmentary fossils from the Denisova Cave in the Altai Mountains of Russia. Because of the fragmentary nature of these fossils, it has been possible to determine little about their original morphology, but DNA has been recovered from the specimens, revealing a great deal of genetic information. Studies of mitochondrial DNA from these specimens has suggested that this group branched off from the lineage that led to modern Humans before the Neanderthal line. However, studies based upon nuclear DNA have suggested that Denisovans and Neanderthals were sister groups, with a common ancestor more recent than their last common ancestor with Modern Humans. While the limited amount of data available makes this hard to resolve, Feng et al. suggest that the Denisovans were probably members of the Homo longi clade, with those morphological traits known all consistent with membership of this group. 

The divergence between the ancestors of Neanderthals and those of Modern Humans was for a long time considered to have happened between 700 000 and 500 000 years ago. However, more recent studies incorporating DNA recovered from Neanderthal specimens have suggested a much earlier split. Feng et al.'s analysis suggests that the Homo longi clade emerged as a distinct lineage about 1.2 million years ago, with Homo sapiens first appearing about 1.02 million years ago, around the time when Yunxian 2 was alive. The Homo longi and Homo sapiens clades are recovered as having diverged about 1.32 million years ago, while the Neanderthal clade diverged from the ancestors of these two groups about 1.38 million years ago.

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Athenar bermani: A new species of Diplodocoid Sauropod from the Late Jurassic Morrison Formation of Dinosaur National Monument, Utah.

In 1913 prolific American fossil hunter Earl Douglass excavated a Sauropod braincase and partial skull roof from the Carnegie Quarry site at Dinosaur National Monument in Utah. This made its way to the collection of the Carnegie Museum in Pittsburgh, where it was given the specimen number CM 26552, and was largely forgotten for half a century (to give some context, Douglass excavated over 300 tonnes of material, including many complete skeletons of Jurassic Dinosaurs such as Diplodocus, Dryosaurus, Stegosaurus, Barosaurus, Camarasaurus, and Brontosaurus, which may have left museum staff a bit busy).

In 1978, palaeontologists David Berman and John McIntosh published a study in which they revised the genera Diplodocus and Camarasaurus, in which they assigned the specimen CM 26552 to Diplodocus. However, since that time our understanding of Sauropods as a group has developed significantly, notably in that proportional differences, which could change significantly as Sauropods grew, are no longer given the same emphasis, with modern palaeontologists instead placing more emphasis on character states (discrete features which can be present or absent).

In a paper published in the journal Palaeontologica Electronica in October 2025, John Whitlock of the Department of Science and Mathematics at Mount Aloysius College and the Section of Vertebrate Paleontology at the Carnegie Museum of Natural History, Juan Pablo Garderes and Pablo Gallina of the Consejo Nacional de Investigaciones Científicas y Técnicas, the Argentina and Fundación de Historia Natural Félix de Azara, and the Centro de Ciencias Naturales, Ambientales y Antropológicas at Universidad Maimónides, and Matthew Lamanna, also of the Section of Vertebrate Paleontology at the Carnegie Museum of Natural History, formally redescribe specimen CM 26552, assigning it to a new species and genus.

Based upon their inspection of CM 26552, Whitlock et al. conclude that it should be placed in the Dicraeosauria, a sub-group of the Diplodocidae, the skulls of which can be determined by (1) the presence of postparietal and frontoparietal fenestrae, (2) the exclusion of the basioccipital from the dorsal margin of the occipital condyle by the exoccipitals, (3) the presence of a distinct prong on the squamosal, (4) the contribution of the frontal to the margin of the supratemporal fenestra, (5) an expanded crista prootica, (6) a free dorsal margin of the antotic process, (7) the presence of a “shelf” overhanging the foramen for the trigeminal (V) nerve, and (8) the flat distal margin of the paroccipital process.

Braincase CM 26552 in anterior (A), (C) and posterior (B), (D) views. Abbreviations: BO, basioccipital; BS, basisphenoid; BT, basal tubera; CPR, crista prootica; EO-OP, exoccipitalopisthotic; F, frontal; LS, laterosphenoid; OS, orbitosphenoid; P, parietal; PO, postorbital; POP, paroccipital process; PR, prootic; S, shelf overhanging the opening for cranial nerve V; SOC, supraoccipital; SQ, squamosal; I, opening for cranial nerve I; II, opening for cranial nerve II; IV, opening for cranial nerve IV; V, opening for cranial nerve V. Whitlock et al. (2025).

Within that group, however, specimen CM 26552 shows a unique combination of features, not seen in any other genera, plus one unique character state,  the presence of a ‘tooth’ in the parietal/opisthotic suture, which has not previously been seen. For this reason, Whitlock et al. assign CM 26552 to a new species and genus, under the name Athenar bermani, where 'Athenar' honours the musician Athenar, 'for whom no better palaeontological comparison exists than a broken skull', and 'bermani' honours palaeontologist David Berman, who did so much of the fundamental modern work on Diplodocoid skulls at Carnegie Museum of Natural History and was responsible for the initial description of the specimen. 

Given the limited material available, no size estimate is made for Athenar bermani, although Whitlock et al. note that it appears to have been larger than the mature Diplodocus CM 11161, but shows incomplete fusion of many of the sutures of the braincase, suggesting that the specimen was a subadult at its time of death. 

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